Understanding the Volatilisation of Alkali and Alkaline Earth Metallic Species during the Pyrolysis of Victorian Brown Coal

摘要

The purpose of this study is to examine the main factors influencing the volatilisation of alkali and alkaline earth metallic (AAEM) species during pyrolysis. Loy Yang brown coal was pyrolysed in a thermogravimetric analyser (TGA), a wire-mesh reactor, a fluidisedbed/ fixed-bed reactor and a two-stage fluidised-bed/fixed-bed reactor under a wide range of experimental conditions. The main factors influencing the volatilisation of Na, Mg and Ca during pyrolysis are the chemical form and valence of AAEM species, the chemical nature of the gas surrounding the pyrolysing particles, temperature, the sweeping gas hydrodynamics (e.g. flow rate) and the interactions between volatiles and char. Other experimental conditions affect the volatilisation of these AAEM species to much lesser extents.